1. Field of the Invention
This invention relates to 3-D (dimensional) image processing technology for performing prescribed image processing to generate, on a display screen, a deformed image obtained by intentional distortion of an original image, for use in for example video game equipment or similar.
2. Description of the Related Art
In recent years, numerous game devices have appeared which display characters (humans or similar) in a quasi-3-D space on a monitor screen. Among such game devices, there are games that mimic skiing, surfing, motorboating, snowboarding, skateboarding, and car racing. In such a game device, when an image of a character moves in a quasi-3-D space, imparting a sense of speed further increases the sense of presence and heightens interest in the game.
On the other hand, in actual photography of skiing, surfing, motorboating, snowboarding, skateboarding, car racing or similar, in order to heighten the sense of presence, techniques are employed in which a fisheye lens is used to increase the sense of speed. Hence in game devices also, by displaying on the monitor screen of the game device an image which appears to have been photographed through a fisheye lens, the sense of speed can be increased and a heightened sense of presence obtained.
Conventionally, in processing to create an image that appears to have been photographed through a fisheye lens (which processing is hereafter called “fisheye processing”), the method described below has been used. First, as shown in FIG. 7A, an original image (a normal image, not appearing to have been taken through a fisheye lens) is divided into small images of a prescribed size. Then, as shown in FIG. 7B, an elliptical region EP (called the “fisheye region”) with center at the image center is described, and each of the small image regions is deformed such that the image in this region appears to have been photographed through a fisheye lens. Then, each of the small images in FIG. 7A is textured, deformed into the corresponding region in FIG. 7B, and pasted into the region.
FIG. 9 is an image obtained by performing fisheye processing, using the method described above, on the original image shown in FIG. 8. As shown in FIG. 9, in the vicinity of the outer border of the fisheye region, straight lines in the original image are deformed into broken-line shapes to form an unnatural image, whereas in the case of actual photography through a fisheye lens, straight lines in the original image are deformed into smooth curves.
The present invention was devised in light of the above problem, and has as an object the provision of a 3-D image processing method and device, a 3-D image processing program, and a video game device which generate, on a display screen, a natural-looking deformed image obtained by intentionally distorting an original image.